1. The effects of subdepressor infusion of prostacyclin (PGI2, 5.3 pmol min−1 kg−1) on arterial pressure and aldosterone production induced by angiotensin II (ANG II) were studied in conscious rabbits.
2. Indomethacin pretreatment caused an augmented blood pressure response after ANG II infusion, which returned to near control level after concomitant infusion of a subdepressor dose of PGI2.
3. Aldosterone production after ANG II was significantly attenuated after pretreatment with indomethacin. PGI2 infusion restored this reduced response to near control level.
4. These results may suggest that PGI2 in the circulation could also serve to modulate the pressor and hormonal action(s) of ANG II.